IL-17A improves the efficacy of mesenchymal stem cells in ischemic-reperfusion renal injury by increasing Treg percentages by the COX-2/PGE2 pathway

Mesenchymal stem cells (MSCs) are effective for the management of experimental ischemia-reperfusion acute kidney injury (IRI-AKI). Immune modulation is one of the important mechanisms of MSCs treatment. Interleukin-17A (IL-17A) pretreated MSCs are more immunosuppressive with minimal changes in immunogenicity in vitro. Here, we demonstrated that administration of IL-17A-pretreated MSCs resulted in significantly lower acute tubular necrosis scores, serum creatinine, and BUN of mice with IRI-AKI, compared with the administration of MSCs. Of the cocultured splenocytes, IL-17A-pretreated MSCs significantly increased the percentages of CD4(+)Foxp3(+) Tregs and decreased concanavalin A-induced T cell proliferation. Furthermore, mice with IRI-AKI that underwent IL-17A-pretreated MSC therapy had significantly lower serum IL-6, TNF-alpha, and IFN-gamma levels, a higher serum IL-10 level, and higher spleen and kidney Treg percentages than the mice that underwent MSCs treatment. Additionally, the depletion of Tregs by PC61 (anti-CD25 antibody) reversed the enhanced treatment efficacy of the IL-17A-pretreated-MSCs on mice with IRI-AKI. Additionally, IL-17A upregulated COX-2 expression and increased PGE2 production. The blockage of COX-2 by celecoxib reversed the benefit of IL-pretreated 17A-MSCs on the serum PGE2 concentration, spleen and kidney Tregs percentages, serum creatinine and BUN levels, renal acute tubular necrosis scores, and serum IL-6, TNF-alpha, IFN-gamma, and IL-10 levels of IRI-pretreated mice with AKI, compared with MSCs. Thus, our results suggest that IL-17A pretreatment enhances the efficacy of MSCs on mice with IRI-AKI by increasing the Treg percentages through the COX-2/PGE2 pathway.